This invention relates to spray-dried detergent compositions and processes for their production. More particularly, it relates to spray-dried detergent compositions containing a water-insoluble aluminosilicate as a detergency builder.
Commonly assigned patent application Ser. No. 450,266 filed Mar. 11, 1974, "Detergent Composition" by John Michael Corkill, Bryan L. Madison and Michael E. Burns discloses the use of certain aluminosilicates as detergency builders. Builders, e.g. sodium tripolyphosphates, are used in detergent compositions for the purpose of tying-up hardness ions normally found in water. In the absence of the tying-up of the hardness ions, the maximum detergency obtainable from the detergent composition is not realized. That is, the hardness ions, normally calcium and magnesium ions, react with the soil and/or the detergent to hinder the cleaning action of the detergent composition. While sodium tripolyphosphate is an excellent builder, there is a concern about its effect on the ecology.
As discussed in the aforementioned copending patent application, a restricted number of aluminosilicates have been found to have utility as builders in detergent compositions. Water-insoluble aluminosilicates of formula EQU Na.sub.z [(AlO.sub.2).sub.z.sup.. (SiO.sub.2).sub.y ]xH.sub.2 O
wherein z an y are at least 6, the molar ration of z to y is from 1.0 to 0.5 and x is from 15 to 264, have been found to be satisfactory for such a use. Conventionally, granular detergent compositions are produced by slurrying all or most of the composition's components and then spray-drying the slurry. Unfortunately, the spray-drying of an aqueous slurry containing the aforementioned aluminosilicate and an organic detergent results in granules which are not crisp and freeflowing. Such attributes are desirable so as to permit the user of the detergent compositon to conveniently pour it from a package and properly measure it prior to its addition to a washing machine. The problem is especially acute in those areas where a combination of high temperature and high humidity causes the detergent composition granules to cake while in the package. While the performance of such a product is not materially affected, the negative effect it has on the consumer is significant.
Various solutions to the problem of caking detergent compositions have been suggested. More moisture-resistant packages is one solution which has been used. Unfortunately, such packages are more expensive. Generally, the addition of components having a known anti-caking effect, for example, sodium silicate, have been used. It is believed that the sodium silicate, together with the aluminosilicate, results in relatively large insoluble particles during the spray-drying operation which, when added to the washing solution, deposit upon the fabrics. Such a deposition is readily noticeable by the consumer.
U.S. Pat. No. 3,328,314 issued June 27, 1967 to Marquis and U.S. Pat. No. 3,424,690 issued Jan. 28, 1969 to Marquis disclosed the use of sodium and potassium sulfosuccinate in detergent compositions containing linear alkyl benzene sulfonate and secondary alkyl sulfates and sulfontes respectively, for an anti-caking effect. However, the use of such compounds in combination with water-insoluble aluminosilicate builders is not suggested. Moreover, it has been found that the addition of the sulfosucinate to an aqueous slurry containing the water-insoluble aluminosilicates has an insufficient effect on the crispness and free-flowability of resultant spray-dried granules having a desirable density.
It has now been descovered that the addition of sodium carbonate and an organic compound having from 1 to 6 carbon atoms substituted with a sulfate or sulfonate group and at least one carboxyl group, when added to an aqueous slurry containing a water-insoluble aluminosilicate and an organic detergent, results in granules produced therefrom by spray-drying which are crisp and free-flowing. Moreover, the granules remain crisp and free-flowing even after extended storage under conditions of high temperature and relative humidity, e.g. 90.degree. F. and 80% relative humidity.
It is accordingly an object of this invention to produce by spray-drying an aluminosilicate-containing detergent composition which is crisp and free-flowing.
Another object of this invention is to produce by spray-drying an aluminosilicate-containing detergent composition which remains crisp and free-flowing after extended storage.
It is still another object of this invention to produce a spary-dried aluminosilicate-containing detergent composition which is crisp and free-flowing by an economical and efficient process.
As used herein, all percentages and ratios are by weight unless otherwise indicated. The weight percent of the aluminosilicate builder is expressed on an anhydrous basis.